1. Field of the Invention
The present invention relates to an apparatus and a method for measuring a diameter of a hole.
2. Description of Related Art
Traditionally, a vernier caliper is normally used for measuring the diameter of a hole. Two measuring claws of the vernier caliper are inserted into the hole touching the inner surface of the hole. Thus the value of the diameter of the hole can be read from the vernier caliper.
Generally, a measured diameter from the vernier caliper is smaller than the actual diameter of the hole.